Put a rack in the center of the oven and heat the oven to 425°F. Line a large rimmed sheet pan with parchment paper or foil for easier cleanup.

Open the can of artichoke hearts and drain them in a colander. If the pieces are large, cut them in half.

Rinse the white beans in the same colander and let them drain well. Pat the beans dry with a clean towel or paper towels so they roast instead of steam.

Pat the chicken thighs dry on a plate. If there are large loose pieces of fat, trim them off.

Put 2 tablespoons of the olive oil, the garlic, dried oregano, 1 teaspoon of the salt, and the black pepper in a large bowl. Stir to make a loose seasoning mixture.

Add the chicken thighs to the bowl and turn them so they are coated on all sides.

Lift the chicken out of the bowl and place it on one half of the sheet pan. Leave a little space between the pieces so the heat can move around them.

Put the bell peppers and red onion into the same bowl. Toss them in the seasoning left in the bowl, then spread them on the empty half of the sheet pan.

Roast the sheet pan for 15 minutes. The vegetables should start to soften, and the bottom edges of the chicken should look opaque instead of raw.

While the first roast happens, put the drained artichokes and white beans in the same bowl. Add the remaining 1 tablespoon olive oil and the remaining 1/4 teaspoon salt, then toss gently.

Pull the sheet pan out of the oven. Turn the chicken over with tongs and stir the peppers and onion so the browned parts move around.

Scatter the artichokes and white beans onto the sheet pan around the chicken. Spread them into as even a layer as you can.