Heat a medium skillet over medium heat and add 2 tablespoons olive oil until shimmering.

Add the 3 cubed boneless skinless chicken breasts and cook, stirring occasionally, until the chicken is cooked through and no longer pink in the center, about 6–8 minutes.

Add 1/2 medium diced red onion and 1 medium deseeded and diced jalapeno; cook, stirring, until the onion and jalapeno are just tender, about 3–4 minutes.

Stir in 14 ounces diced tomatoes with peppers and 10 ounces enchilada sauce; bring to a gentle simmer and cook, stirring occasionally, until heated through, about 3–5 minutes.

Evenly sprinkle 2 cups crumbled tortilla chips over the skillet mixture.

Evenly top the chips with 8 ounces grated Monterey Jack cheese.

Cover the skillet with a lid and cook over low–medium heat until the cheese has melted, about 2–4 minutes.

Remove from heat and serve warm. Garnish with sour cream, if desired.