Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Rinse the chickpeas thoroughly and pat them completely dry with a clean kitchen towel; removing any loose skins will help them get extra crispy.
Cut the chicken breast into bite-sized 1-inch cubes and place them in a large mixing bowl with the dried chickpeas.
Add the olive oil, dried oregano, garlic powder, sea salt, and black pepper to the bowl, tossing everything until evenly coated.
Spread the chicken and chickpeas in a single layer on the prepared baking sheet, ensuring they are not overcrowded.
Roast for 20-25 minutes, shaking the pan halfway through, until the chicken is cooked through and the chickpeas are golden and crunchy.
Remove from the oven and immediately toss with the fresh lemon juice and lemon zest while still hot.
Place the fresh baby spinach in a serving bowl and top with the hot chicken and chickpea mixture, allowing the greens to slightly wilt from the heat before serving.