In a saucepan, combine blueberries, sugar, and peach nectar. Simmer over medium heat for 10 minutes, stirring and mashing berries.
If needed, mix cornstarch with water and stir into the sauce. Cook until thickened, then cool.
Preheat oven to 350°F (175°C) and line a muffin tin with liners.
Pulse graham crackers into crumbs, mix with sugar and melted butter, then press into muffin cups.
Bake crusts for 10 minutes and let cool.
Beat cream cheese and sugar until smooth. Add eggs, flour, vanilla, lemon zest, and lemon juice. Mix on low until smooth.
Divide filling into cups and bake for 18–22 minutes until centers slightly jiggle.
Cool for 30 minutes, then refrigerate for at least 1 hour.
Top each with blueberry sauce to finish your Blueberry Topped Mini Cheesecakes.