Prep all the vegetables. Make sure to squeeze excess liquid out of the zucchini and measure after removing liquid. dice chard, onion, and garlic fine.
Combine all ingredients in a medium-sized bowl. Don't overwork the mix.
Spray a large skillet with olive oil and heat to medium-low heat.
Use a rounded ½ cup to scoop and form each burger patty. Press each patty flat until it's about 4 ½ inches in diameter. Option to make smaller and more condensed patties with only ⅓ cup.
Once skillet is hot, grill patties for about 5-8 minutes per side, or until each side is browned. Press down lightly on patties with spatula to help it keep its size and not shrink down. Start the cook covered to decrease cook time, but remove lid when flipping the patty.Drain any excess liquid out of the pan as it cooks for a more flavorful and brown grill. Option to cook on grill, they will hold together!