1) Add tequila, mango juice, lime juice, and a pinch of chili powder to a cocktail shaker filled with ice. 2) Shake vigorously until the shaker is frosty. 3) Fill a tall glass with fresh ice and strain the mixture into the glass. 4) Slowly pour the grenadine down the inside of the glass so it settles on the bottom for a sunrise effect. 5) Garnish with fresh mango slices and serve immediately.