In a medium saucepan, combine rice, water (or chicken broth), taco seasoning, and butter. Bring the mixture to a boil, then reduce the heat to low. Cover and simmer for 15-20 minutes, or until the liquid is fully absorbed and the rice is tender. Fluff with a fork and set aside to cool slightly.

Heat a skillet over medium heat and cook the ground beef until browned, breaking it into small crumbles as it cooks. Drain excess grease, then stir in the taco seasoning and water. Let the mixture simmer for 5 minutes, allowing the flavors to meld. Remove from heat and set aside.

Heat a non-stick skillet over medium heat. Place one tortilla on the skillet and sprinkle an even layer of shredded cheese over the surface. Place a second tortilla on top. Cook for 1-2 minutes on each side, or until the cheese is fully melted and the tortillas are lightly golden. Repeat with the remaining tortillas to create four quesadilla 'shells.'

Lay one quesadilla flat on a clean surface. Spread 2 tablespoons of sour cream in the center, followed by a drizzle of nacho cheese sauce. Add a scoop of the seasoned rice, then top with a layer of the spiced ground beef. If using salsa, add a spoonful for extra flavor.

Fold the sides of the quesadilla over the filling, then roll tightly into a burrito shape. Repeat with the remaining quesadillas and fillings.

Heat a skillet over medium heat and place the assembled quesaritos seam-side down. Cook for 1 minute on each side, or until lightly golden and the edges are sealed.

Slice each quesarito in half and serve warm with additional sour cream, salsa, or guacamole on the side.