Preheat the oven to 425F. Give the potatoes and poblano a good rinse.
Dice up the potatoes into bite sized chunks, somewhere between 1/4" and 1/2" wide. Dice up the poblano and 1/2 onion into slightly smaller sized chunks (be sure to discard the poblano seeds.)
In a mixing bowl combine the potatoes, poblano, 1/2 onion, 4 whole peeled garlic cloves, 2 tablespoons olive oil, 1 teaspoon salt, and freshly cracked black pepper. You can optionally add 1/2 teaspoon of hot chili powder.
Spread the mixture into an even layer on a baking sheet. (I line the baking sheet with parchment paper for easier cleanup but cooking them directly on the pan will crisp them up more.)
Bake at 425F for 30-40 minutes, stirring them at least once while they are baking.
Take a final taste for seasoning. I added another generous pinch of salt to this batch. Serve immediately.