Getting around Chun’s fireballs is really your biggest hurdle. If you can manage to accomplish that, the match isn’t so hard.
Hundred Hand Slap is really good against Chun, 'cause she doesn’t have anything solid to beat it consistently. So say you j.Forward over a fireball, hit or blocked, you’re guaranteed some free chip damage with hands unless she has super.
She also has a tough time with the butt slam in the corner. If she doesn’t predict it, the only thing she can really do is Short upkicks, but that’s kinda hard to time.
Also, just his regular punches (st.Jab and st.Strong especially) are great pokes. If you’re in close, but not close enough for an Ochio, you can do a st.Jab or st.Strong and keep mashing on punch to get free block damage. Charge down while you’re doing this, so that if she throws a fireball, you can butt slam.
That’s my random advice for now.