Preheat the oven to 400°F. Line a baking sheet with parchment paper.
In a food processor, combine 2 1/2 cups fresh baby spinach and 3 garlic cloves. Pulse until the spinach is chopped into small pieces but not pureed.
With the processor running briefly, drizzle in 1 tablespoon olive oil, then add half of the crumbled feta. Pulse just a few times to combine. Transfer this spinach–feta mixture to a large bowl.
To the bowl, add 1 pound lean ground chicken, 1 large lightly beaten egg, 1 tablespoon Worcestershire sauce, 1/4 teaspoon salt, 1/4 teaspoon pepper, 3 tablespoons fresh oregano, and 1/3 cup seasoned panko breadcrumbs. Mix gently with your hands until just combined. If the mixture is too wet to shape, add more breadcrumbs a little at a time up to 1/2 cup.
Add the remaining crumbled feta to the mixture and fold in until evenly distributed.
Form the mixture into about 30 mini meatballs (roughly 1/2‑inch diameter). Arrange them in a single layer on the prepared baking sheet, leaving a little space between each.
Bake the meatballs 20–25 minutes, or until cooked through and no longer pink in the center. Remove from the oven and keep warm.
While the meatballs bake, spiralize 2 medium zucchini into noodles. Heat a large skillet over medium‑low heat and add 2 tablespoons olive oil and 1 tablespoon unsalted butter. When the butter has melted, add 2 minced garlic cloves and a pinch of red pepper flakes and cook about 1 minute, until fragrant. Stir in the juice of 1 lemon.
Add the zucchini noodles to the skillet and toss to coat in the oil–butter mixture. Cook, tossing often, about 5–6 minutes, until the noodles are slightly softened but still hold their shape.
To serve, place a bed of zoodles on each plate, top with the mini chicken, feta, and spinach meatballs, and sprinkle with extra crumbled feta and additional fresh oregano.