Heat medium skillet over medium-high heat. Add oil. Add chicken and cook until browned, 5 to 7 minutes. Mix in taco seasoning. Remove from heat and set aside.

Preheat the oven to 350 degrees F (175 degrees C).

Combine eggs, Cheddar cheese, milk, red bell pepper, shallot, mushrooms, chives, jalapeno, hot sauce, salt, and pepper in a large bowl. Fold in cooled chicken mixture.

Pour mixture into nonstick mini muffin tins, filling each cup 3/4 of the way.

Bake in the preheated oven until eggs are set, about 18 minutes.