In a large pan or wide pot, sauté onion, red bell pepper, and celery in oil over medium heat for 2 to 3 minutes until softened and fragrant.
Add minced garlic, chili powder, paprika, onion powder, and cumin and combine with the vegetables, stirring frequently for about 3 minutes.
Add the cooked lentils, fire-roasted tomatoes, coconut sugar, low-sodium vegetable stock, sea salt, and ground black pepper and stir to combine. Bring the mixture to a simmer for a couple of minutes, then reduce heat to medium-low and cook for another 10 to 12 minutes, stirring frequently. Keep the chili warm until you're ready to serve your nacho platter.
Assemble your nachos however you like. Feel free to use other toppings to your liking. Arrange the tortilla chips on a large platter, top with warm lentil chili, fresh tomatoes, green onion and pickled jalapeños, then drizzle with lots of nacho cheese. You can pile that chili as high as you want, or even think about making single serving chili nacho bowls for Super Bowl Sunday!