Combine 2¾ cups milk, 2¼ cups oats, ½ cup yogurt, ¼ cup pistachios, 1 tablespoon each confectioners’ sugar, chia seeds and vanilla and ¼ teaspoon salt in a medium bowl; stir to mix well. Cover and refrigerate for at least 8 hours.
Spread ¾ cup ricotta on a paper-towel-lined plate; top with more paper towels. Gently press down to remove excess moisture; let stand at room temperature for 10 minutes. Transfer the ricotta to a small bowl.
Whisk 1 teaspoon orange zest and the remaining 1 tablespoon confectioners’ sugar and ½ teaspoon vanilla into the ricotta until fully combined.
Spoon ½ cup oat mixture into each of 4 (8-ounce) jars. Top each with 3 tablespoons ricotta mixture, then top each with ½ cup oat mixture.
Stir 3 tablespoons chocolate chips and 1 teaspoon coconut oil together in a small microwave-safe bowl. Microwave on High until the chocolate chips are melted, 45 to 60 seconds. Stir until the chocolate chips are completely melted and incorporated into the oil. Spoon about 2 teaspoons of the melted chocolate over each jar, spreading to cover the entire surface. Refrigerate, uncovered, until the chocolate layer is almost fully set, about 5 minutes. Sprinkle the chocolate with the remaining 1 tablespoon pistachios. Refrigerate the jars, uncovered, until the chocolate is fully set, about 5 minutes.
