Impressive Pepperoni Queso

Vegetable oil 1 white onion, diced 1 (4-oz.) can chopped green chiles ½ (10-oz.) can diced tomatoes with green chiles 8 oz. Velveeta cheese, cubed 8 oz. sharp cheddar cheese, shredded 1-2 fresh jalapenos, seeded and diced ½ c. sliced…