In a large skillet, heat the olive oil on low-medium heat. Add sliced onions with a pinch of salt, and let caramelize until soft and golden, about 10 minutes. While onions are cooking, dump enchilada sauce into a bowl and whisk in Buffalo sauce until combined.
Add shredded chicken to onions with BBQ seasoning and a pinch of cayenne pepper. Mix thoroughly. Pour in about a half of a cup of the enchilada/Buffalo sauce mixture and add half of the cheddar cheese and half of the Colby cheese. Stir until the mixture comes together and turn off the heat.
Pour a drizzle of enchilada/Buffalo sauce in the bottom of a baking dish.
Take each tortilla and fill it with a little over half a cup of the chicken mixture. Roll each up and set it in the baking dish. Dump the remaining enchilada/Buffalo sauce on top of tortillas and add the remaining cheese.