Combine beef and chicken broth in a medium saucepan, heat to a boil and reduce until 2 1/2 cups remain, about 45 minutes.

In heavy large saucepan, heat 2 tablespoons of the oil over medium-high heat.

Add shallots and cook until tender, about 4 minutes.

Add broth reduction, marmalade and chipotles.

Simmer until mixture is reduced to 2 cups, about 5 minutes.

Mix 1 tablespoon water and cornstarch in a small bowl.

Whisk cornstarch mixture into sauce and stir until sauce boils and thickens, about 5 minutes.

Season with salt and pepper and remove from heat.

Preheat the oven to 425°F.

Season pork with salt and pepper.

Heat remaining 1 tablespoon oil in a large, heavy oven-proof skillet over high heat.

Add pork and brown on all sides, about 4 minutes.

Transfer skillet to oven and bake until thermometer inserted into pork registers 155°F, about 15 minutes.

Remove from oven and let pork rest for 5 minutes.

Bring sauce back to a simmer.

Slice tenderloins into 1/2-inch thick medallions and arrange on plates. Spoon sauce over the top and serve.