Preheat oven to 400 degrees.

Trim tenderloin of excess fat and silver skin.

Mix together brown sugar, kosher salt, garlic powder, onion powder, paprika, black pepper and chili powder until completely combined. Rub entire amount of spice mixture on tenderloin then drizzle olive oil evenly over top.

Roast until nicely browned and internal temperature reaches 150 degrees (approximately 25−35 minutes depending on size).

Remove from oven, brush with barbecue sauce if desired and allow to rest 5 minutes.

Slice and serve.