Bring the milk to a boil in a heavy medium-sized saucepan. Remove from heat and stir in the tea leaves. Cover and set aside to steep for 10 to 15 minutes.
Meanwhile, beat the egg yolks and sugar until thickened and pale yellow in a medium mixing bowl. Beat in the cornstarch.
Place a fine mesh strainer over a 2 cup (or greater) glass measuring cup with a pouring lip. Pour the milk and tea leaves through the strainer, pressing on the solids to force the milk into the cup. Add the milk in a steady stream to the egg mixture, beating until well combined. Pour back into the pan and heat over low heat, stirring constantly until custard begins to thicken. Don't let the mixture come to a boil, or you risk scrambling the eggs.
Remove the custard from the heat and pour through a strainer into a large clean bowl - to remove any egg solids. Allow the custard to cool slightly, then stir in the cream. Cover and refrigerate until well chilled - at least 2 hours or overnight.
Stir the chilled custard then churn the ice cream according to your manufacturers instructions. When the ice cream begins to firm up, add the pistachios and chocolate chips. Continue to process for 5-10 minutes. When finished the ice cream will be soft but ready to eat. For firmer ice cream, transfer to a freezer safe container and freeze at least two hours.