1. Season chicken with salt and pepper. Heat a large skillet over medium-high; melt 2 tablespoons butter. Add chicken; cook, flipping once, until golden brown, 5 to 7 minutes. Stir in vinegar, scraping up browned bits from bottom of pan; cook 30 seconds. Add broth; simmer, turning chicken frequently, until cooked through and coated with sauce, 3 to 4 minutes. Transfer to a bowl.

2. Wipe skillet clean; heat over medium. Melt remaining 2 tablespoons butter. Stir in chopped scallions; cook just until fragrant, about 1 minute. Add corn; cook just to heat through, about 1 minute. Add cream cheese and milk. Cook, stirring, until cheese melts and simmers, 2 to 3 minutes. Season with salt and pepper. Top chicken and corn with sliced scallions; serve, with arugula salad.