Mexican style taco cheese
We do a fajita night once a week in my house; so I have tuned the following recipes over the last 10 years or so.  

1/2 tsp of each:
ground cumin
onion powder
salt
chili powder
cornstarch (ONLY if melting cheese)
crushed red peppers (optional for spicy)
garlic powder
oregano leaves
(Heavy cream and butter if melting)


Cheese base is pending my mood; queso fresca, standard white sauce with cheddar or some fancy mexican blend with the standard, colby/cheddar/jack...  

Based on your post i would recommend the colby/cheddar/jack with spices (can we call that the fajita trinity?).