Preheat air-fryer to 325°. Line a 6-in. square or round cake pan with parchment, letting ends extend up sides. In a small microwave-safe bowl, melt butter and 1 cup chocolate chips; stir until smooth. Cool slightly. In a small bowl, beat eggs and sugar. Stir in water and vanilla extract. Combine flour, baking soda and salt; gradually add to chocolate mixture. Fold in remaining 1/2 cup chocolate chips., Pour into prepared pan. Bake until a toothpick inserted in center comes out with moist crumbs (do not overbake), 40-45 minutes. Tent with foil as needed to prevent overbrowning. Cool on a wire rack., Lifting with parchment, remove brownies from pan. Cut into squares.