This lean burger gets plenty of flavor and juiciness from canned green chiles and fresh cilantro. Finish with sour cream for a creamy spread with a little extra tang.
Heat grill to medium-high. Combine chicken, cumin, chiles, chopped cilantro, and 1/2 teaspoon salt; season with pepper. Divide mixture into 4 patties. Brush grates with oil and grill burgers, flipping once, until golden brown and a thermometer inserted into thickest parts registers 165 degrees, 8 to 10 minutes.
Lightly brush tomato slices with oil; grill, flipping once, until charred, 2 minutes. Season with salt. Grill buns, cut-sides down, just until toasted, about 1 minute. Serve burgers on grilled buns with tomato slices, cilantro sprigs, sour cream, lettuce, and mustard.