Cut all cheeses into cubes for easier and quicker melting. Preheat a pellet grill or smoker to 225°F.

Place the cubed cheeses into a heat-safe pan and set on the smoker. Allow to melt and smoke for 1–2 hours, stirring occasionally, until piping hot and fully melted.

While the queso is smoking, add the Rotel tomatoes, green chiles, salt, pepper, and milk to the cheese mixture. Stir well and continue to smoke while preparing the steak.

Preheat a griddle or flat-top grill on high heat until very hot.

While the griddle preheats, dice the onion and cut the steaks into strips. Season all sides generously with steak seasoning, salt, and pepper.

Lightly oil the griddle and add the steak strips. Cook for about 5 minutes total, turning as needed, until cooked to your desired doneness but still slightly pink and juicy.

Remove the steak from the griddle. Cook the diced onion in the leftover steak juices until softened.

Stir the cooked onions into the smoked queso.

Chop the steak into bite-sized pieces and garnish over the queso.

Serve immediately with tortilla chips.