Preheat oven to 350 F. Prepare Rice-A-Roni according to package directions. While that is cooking, shred/cut up the chicken (I always use a rotisserie chicken, but you could use leftover chicken or some cooked and shredded breasts, whatever), removing meat from bones.
When Rice-A-Roni is done, add the can of soup and the sour cream, and stir to combine. Add the chicken and mix together. Spread mixture into a sprayed baking dish (I use a 9-by-13-inch pan, but you can use what you like for how thick you want it to be) and bake, uncovered, at 350 F for 40 minutes.
Remove from oven, cover with the french-friend onions and bake for 5 more minutes. Remove from oven and try not to eat the whole thing. Yum!