You certainly could use macaroni and cheese powder to top other foods, wet or dry. It comes in a shaker, did you know? At least it used to...for things like popcorn, and your chex mix. Try it on mashed potatoes, or on ramen, or anything that you want cheesy. But the cheese packet out of the box dinner is the same thing, and next time you make a casserole or whatever, you can use up the noodles.

You could add meat flavoring by crushing a cube of bouillon into it. Similar is a ramen noodles flavor packet.

I don't know the flavor you are going for, I have never eaten that chex stuff but you could also use cajun seasoning, chili powder, Mrs. Dash (one of these is a chipotle flavor which is smoked jalepeno).

Make sure you know if something is going to add salt to your finished dish. If you use a little bit of a few different salty seasonings, you will oversalt your chex mix! It is easy to do!