This crowd-pleasing recipe was sponsored by Mi Niña Tortilla. 

serves 6-8 

Ingredients
1 tbsp olive oil
1/2 yellow onion, diced
1 poblano pepper, seeded and diced
1 serrano chili, minced
1 tsp chili powder
1/2 tsp cumin
kosher salt, to taste
10oz can diced tomatoes with jalapeño
12 oz beer (we used a lager, but any light beer would work)
12 oz sharp cheddar cheese, grated
12 oz monterey jack cheese, grated
3 tbsp cornstarch 
Mi Niña Tortilla Chips, for serving

Optional Nacho Toppings: thinly sliced radishes, thinly sliced red cabbage, thinly sliced jalapeño, thinly sliced serrano, drained and rinsed black beans, avocado slices, fresh cilantro, diced red onion, fresh lime juice 

Directions
Turn the Instant Pot® on to the SAUTE function and add olive oil. Add onion, poblano and serrano and cook for about 3-5 minutes, or until softened. Add the chili powder, cumin and salt and cook for an additional minute or two, or until very fragrant. Add beer and diced tomatoes, scraping the bottom of the pan and stirring to combine.

Meanwhile, toss the grated cheese with the cornstarch, stirring well to make sure each shred is coated with the cornstarch.
Add the lid to the Instant Pot® and make sure the vent is set to "sealing". Set the pot to MANUAL, high pressure, and cook for 5 minutes. Let release naturally for about 5 minutes, then release the rest of the pressure manually.

Carefully remove the lid, then working quickly, add the cheese into the beer mixture, whisking vigorously to combine. Once all of the cheese has been incorporated, set pot to KEEP WARM function and serve. Stir occasionally to prevent the cheese from getting lumpy.

To make nachos, scatter Mi Niña Tortilla Chips on a platter and ladle on the cheese sauce. Add toppings of choice and enjoy!

Note: If you do not have a pressure cooker, you can make this in a pot on the stove. Heat a medium saucepan over medium high heat and add the olive oil. Sauté the onion and pepper until soft (about 5 minutes) then add the spices, followed by the beer and the diced tomatoes. Cover and simmer for about 7 minutes, then whisk in the cornstarch-coated cheese as noted above.
Store any leftover cheese in the fridge. To reheat leftovers, set up a double boiler (a pot of 2 inches of simmering water topped with a heat-proof bowl). Add the cold cheese to the bowl and gently reheat, whisking until it becomes smooth and is heated through.