Oh, yes, I imagine there will be many
Twi'leks running around the galaxy in TOR - especially female ones.
If the only appearance of the Chiss that you've read is the Thrawn trilogy, it's understandable that you'd forget. Thrawn himself, after all, was the only Chiss to appear in that trilogy. The species didn't start getting fleshed out until Luke and Mara Jade's adventures in the Hand of Thrawn duology. I find them a pretty compelling species and I'd really like to get a more in-depth look into their society, but who knows if that will ever happen.
I'm thinking my first character will be an Imperial Agent, and - even though I've decried the inclusion of the species above - possibly as a Chiss. My second will, naturally, be a Jedi, though I haven't bothered giving any thought to a species yet. Plenty of time still, right?