This one is so easy and tastes so good. The kids end up just eating tortillas and cheese, but maybe yours aren't as picky as mine. Good luck.
Chicken (I use 2 boneless/skinless breasts)
1 red bell pepper
1 green bell pepper
McCormick Fajita Seasoning Pack
Thinly slice chicken and cook in a little oil. Set aside in a dish then slice the onion and bell peppers and saute in a little oil. Add chicken back to the mix and add the seasoning packet and a little water. Mix well. Serve on warm tortillas with sour cream and shredded cheddar or whatever you like. I like the McCormick seasonings because it has a hint of lime.