What would be good substitute for Thyme and Oregano in Chili
There is tremendous variation in how chilis are flavored; if you have three chili cooks in the room, you probably will have six  different opinions.

The most traditional flavor base is built on chili and cumin, plus (depending on region and variant), tomatoes, onions and/or garlic.

After that, you get into preference.  Some cooks don't add any herbs at all.  Others add complex blends of spices (even chocolate) rivaling some of the mole sauces of Mexico.

I think the most compatible herbs for chili include include Mexican oregano (which is a different herb than oregano), so if you can get it, it is the best choice, oregano (as you have already mentioned), and thyme.  I do like to put a bay leaf or three in my chili although that may not be traditional.

Still, if you don't have them available or cannot use them for some reason, leaving them out is a fine option.