Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Pat the cubed chicken breast and rinsed chickpeas thoroughly dry with paper towels to ensure they get crispy.
In a medium mixing bowl, combine the chicken, chickpeas, olive oil, lemon zest, dried oregano, sea salt, black pepper, and minced garlic.
Toss the ingredients until everything is evenly coated in the oil and spices.
Spread the mixture onto the prepared baking sheet in a single layer, ensuring enough space for air to circulate.
Roast for 18 to 20 minutes, tossing the ingredients halfway through, until the chicken is cooked through and the chickpeas are golden.
Remove the tray from the oven and immediately drizzle the fresh lemon juice over the hot mixture.
Place the fresh baby spinach in a serving bowl and top with the hot chicken and chickpea mixture, allowing the heat to gently wilt the greens before serving.