There’s a few tricks for this.
First, you can try adjusting your input method by developing a specific motion that works for you. For example, instead of simply doing :d: then :u:, you can do a motion like :d::df::f::uf: then tap the :h: once you feel the stick hit the corner of the square gate (this of course assumes you use a stick, but I imagine you could come up with something similar on pad).
Second, you can adjust the combo to accommodate your trouble spots. For the combo that I posted, you can easily do this by replacing the cr.s that follow each SBK with a Lightning Legs H. The extra hitstun will prevent you from developing the combo much further, but if you’re just interested in getting the 650-700k that I mentioned, then by all means you should do this. Take the easy way with Chun when you can, because it’s not often that you have that luxury.
Here’s a simplified version of the combo (note that this removes the room for growth by increasing its ease of execution). Linking from Lightning Legs into cr.H is extremely lenient.
cr. st.:h: xx Kikoanken
st.:h: cr.:h: (jump cancel) :d:+:m: xx Air Dash, j.:h:, (land)
[cr.]* cr.:h: xx TK SBK H, (land)
Lightning Legs H, cr.:h: xx TK SBK H, (land)
Lightning Legs H xx Kikosho Hyper
*you can choose to keep or discard this cr.. I find that going straight into cr.:h: is just as easy, so I personally opt to remove it. You might even be able to fit in a 3rd SBK loop by doing so, but the timing for this would be tight.
I more or less got it now TKing a qcf motion did the trick. Thanks a million! I just have to stay in training a while to get it consistent.
And I’ve noticed, sometimes the cr. after the stomp into airdash doesn’t connect and they just flip out I guess I’m just too slow and HSD is too much or I do the stomp a little too high. Oh well. At least I can just go for the cr.:h: consistently offline.
Sigh I hate trying to make up combos with her. I mean small hitboxes plus hitstun deterioration… Man one buff I wish they gave her was easier time comboing during jump cancel-ed crap >.< It’s so strict on timing sometimes.
Here’s another combo. It’s sort of a mish-mash of all her combo strings.
cr. st.:h: xx Kikoanken
st.:h: cr.:h: (jump cancel), :d:+:m: xx Air Dash, j.:h:, (land)
st. st.:h: cr.:h: (jump cancel), :d:+:m: j.:h::s:, (land)
cr.:h: xx Lightning Legs H, cr.:h: xx TK *SBK H, (land)
cr.:h: xx Lightning Legs H xx Super
Does ~700k for 1 bar and builds over a bar. You can DHC into Storm for almost 900k to kill half the cast in 1 touch. Kikosho also props the foe high enough that Storm can link Elem. Rage after Hailstorm, which is ~1 mil for 3 meters.
*Edit: Failed to mention that the SBK can be an EX-SBK (thanks Sekirei!).
*Edit2: Failed to mention that the EX-SBK version is extremely difficult and not recommended for consistency’s sake (thanks Nick!).
Tiger Knee’d Spinning Bird Kick. :qcf::uf: :h: Basically you’re cancelling H into a jump cancel and as soon as you lift from the ground an insta-air SBK should come out, you can’t follow up a grounded SBK w/o X-Factor but instant air SBK nullifies that and it’s safer on block
I probably played mag iron man sentinel that day but it could have been dr strange dormammu doom. I think i was learning how to play magneto and ironman
I can’t seem to to airdash H after the Yosokyaku… Chun keeps going over them and miss with the punch. Also for the SBK is it possible to do a EX version and do the same thing after?
About the stomp/dash/H: you need to input the stomp/dash as soon as you leave the ground. I personally just double tap :d:+:l:+:m:. This will cancel the stomp into your airdash immediately and keep you at the appropriate height. Then just tap :h: a short moment after.
You can also opt to skip this portion of the combo and it still works. You could even add something else later.
About the SBK: yes it should be the EX version, sorry I should have mentioned this.
When exactly are you charging for the EX SBK during this part of the combo? I can only manage to get a hard SBK instead of an EX. I’ve tried waiting as long as I could before I do the crouching hard after the hard LL, but they fall out before I’m completely charged.
I typically just do the H version of the SBK instead. I personally wouldn’t recommend going for the EX, but I posted it up there for completion’s sake. I think I’m gonna go back and change it yet again.
As for the how, the EX one is somewhat impractical. To get the EX (I think I’ve only ever done it once just to confirm that it’s possible), you need to just briefly flick your stick upward for the j. that follows the j.:d:+:m: then immediately return to holding down charge. It’s insanely tight and not worth it imo.
I’ve got another really flashy one that looks like Brian’s old BnB but a bit easier on execution. To give proper credit to Brian Kasugano, I generally refer to [:d:+:m: j.:h::s:] as the BK stomp string lol.
I’m polishing it a bit more and I think I might be able to get 3 BK loops in one combo. Easily one of Chun’s prettiest combos. And yes, pretty is important. Flashy or go home.
I had a suspicion that was how it was done. I can do the combo with relative ease, but I was too stubborn to only be satisfied with a hard SBK if an EX was practical. Now that I know I can stop trying it. Thanks for answering my question.
s that follow each SBK with a Lightning Legs H. The extra hitstun will prevent you from developing the combo much further, but if you’re just interested in getting the 650-700k that I mentioned, then by all means you should do this. Take the easy way with Chun when you can, because it’s not often that you have that luxury. 
I guess I’m just too slow and HSD is too much or I do the stomp a little too high. Oh well. At least I can just go for the cr.:h: consistently offline.