Heat the olive oil in a large skillet over medium-high heat. Add the spinach, season liberally with salt and pepper, and cook, stirring often, until spinach is wilted, 2 to 3 minutes. Remove from the heat.
In a medium bowl, combine the cooked spinach, cream cheese, mozzarella, and garlic powder, and stir to combine.
Slice chicken breasts in half crosswise. Cut a slit into the center of each half to make a pocket. Take a heaping spoonful of the spinach dip and pack it into the pocket. Pinch the edges of the chicken closed.
Place the flour, eggs, and breadcrumbs in three separate bowls. Take 1 piece of stuffed chicken and roll it in the flour, shaking off any excess. Dip the floured chicken in the eggs, then dredge in the bread crumbs, making sure to coat all sides evenly. Repeat to bread the remaining chicken.
Heat the canola oil in a skillet over medium-high heat. Fry the chicken until the bread crumbs are golden brown, about 4 to 5 minutes per side. Remove from pan and drain. Serve!