In a medium pot over low heat, add the evaporated milk and warm gently. Do not boil.
Slowly add the shredded pepper jack and white American cheese, stirring constantly until fully melted and smooth.
Stir in the drained jalapeños and diced tomatoes.
Add salt, onion powder, garlic powder, and cumin.
Mix well and cook for another 1–2 minutes until the queso is creamy and heated through.
The cheese will thicken as it cools down.