Preheat a 3 or 5-quart sauté pan over medium-high heat until rim of pan is hot. Add oil and wait another minute. Add pork and cook, turning as needed, until browned on all sides (about 4 minutes).
Transfer meat to a 9 x 13 inch baking pan and bake in a 400 F oven until a meat thermometer inserted in thickest part of tenderloin registers 160 (about 15 minutes).
Meanwhile, discard fat from sauté pan and add port and broth. Bring to a boil over high heat; then boil, uncovered, until reduce to about 3/4 cup (about 3 minutes). Stir in cream and continue to boil, stirring, until sauce is covered with large, shiny bubbles (about 5 more minutes). Add cheese and stir until melted; stir in chiles. Remove from heat.
To serve, thinly slice meat across the grain. Fan out slices on individual plates and spoon sauce over them.