Preheat your oven to 350 degrees F. Line a rimmed baking sheet with parchment paper.

Take a large nonstick pan, pour the oil in it, and place it over medium heat on the stove.

Peel the skin off the onion and use a large sharp knife and cutting board to slice it into thin layers. Place the sliced onion in the pan, turn the heat to low, and cook for 8 to 10 minutes. While the onion is cooking, remove the seed and stems from the bell peppers. Use the knife to cut the pepper into strips the cut the strips into thirds or fourths, depending on your preference. Add the cut bell pepper into the pan with the onion. Sprinkle the kosher salt onto the veggies and cook for another 5 to 7 minutes, until softened.

While the peppers and onions are cooking, lay the tortilla chips out in a crowded single layer on top of the parchment paper. Make sure there are no spots where you can see the parchment paper - you want to try and get the toppings on as many chips as possible and not have them fall through to the bottom of the pan.

Use the knife and cutting board to chop the cooked chicken into quarter-inch to half-inch pieces. Sprinkle the pieces evenly over the tortilla chips.

Once the veggies are done cooking, spread them in an even layer on top of the tortilla chips and chicken. Do the same with the shredded cheese, covering each chip as best you can.

Place the sheet pan in the oven and cook for between 12 and 20 minutes, depending on how big and how hot your oven runs. Check the nachos after 10 minutes to see how fast the cheese is melting and cook in 3 minutes increments until the cheese is melted to your liking and starting to brown. Remove the sheet pan from the oven and serve the nachos with whatever toppings you like.