Start by cooking your noodles by package directions until just al dente (firm to bite and not quite cooked through, as they will cook a little more when added to the recipe).
While your noodles are cooking, heat a large skillet or cast iron over medium high and add sunflower oil. Reduce heat to medium and sauté onions for a couple of minutes until just soft.
Add minced garlic, chili powder, cumin, and paprika and sauté for a few more minutes until fragrant. Then add the beefless ground to pan and continue to cook, stirring frequently until it starts to brown and cook through. Slowly add reserved pasta water a little at a time using just enough to keep from sticking.
When pasta is cooked, drain and immediately add it to skillet tossing gently. Add nacho cheese sauce as well as salt and pepper to taste and any additional pasta water until desired consistency reached. Note: you may want to reserve a bit of cheese sauce for serving or reheating.
Garnish with green onion and tomato and serve immediately.