Heat broiler. Place the pork on a foil-lined rimmed baking sheet. Rub with 1 teaspoon of the oil, the chili powder, and 1/4 teaspoon each salt and pepper. Broil, turning occasionally and basting with the maple syrup twice, until cooked through, 10 to 12 minutes.
Let rest for 5 minutes before slicing.
Meanwhile, in a food processor fitted with the coarse grating disk, grate the sweet potatoes.
Heat the remaining tablespoon of oil in a large nonstick skillet over medium-high heat.
Add the shallots and cook, stirring occasionally, until beginning to brown, 2 to 3 minutes.
Add the sweet potatoes and cook, tossing occasionally, until tender, 7 to 9 minutes more.
Add the spinach and cook, tossing, until just wilted, 1 to 2 minutes more.
Serve the pork and potatoes with the hot sauce, if desired.
Notes:
we enjoyed this recipe, but used hot chili powder... next time, we would be more careful so that it doesn't end up too spicy.