In a shallow bowl whisk together olive oil, lime juice, chili powder, brown sugar, cumin, paprika, onion powder, garlic powder, 1 teaspoon salt, 1/2 teaspoon black pepper, and a pinch of cayenne to make the marinade.
Add the chicken tenders (or breasts) to the marinade, turning to coat; marinate at least 15 minutes.
Meanwhile, bring a large pot of salted water to a boil and cook the penne according to package directions until al dente; drain and set aside.
Heat a grill or grill pan to medium. Grill the marinated chicken, covered if using a grill, until browned on the first side, then flip and cook until cooked through (internal temperature 165°F); remove and let rest.
In a large skillet over medium-high heat melt the butter. Add the chopped onion and cook 3–4 minutes until softened.
Add the minced garlic and cook about 30 seconds until fragrant, then sprinkle in the flour and stir to combine.
Gradually whisk in the chicken broth and milk until smooth and starting to thicken.
Stir in the cubed cream cheese until melted and the sauce is creamy; season with salt and freshly ground black pepper to taste.
Add the cooked penne, diced tomatoes, and chopped parsley to the sauce and toss to coat evenly.
Slice or place the grilled chicken on top of the pasta and sprinkle with freshly grated Parmesan if desired; serve immediately.