In a small saucepan over medium heat, combine the apricots, cherries, ¼ cup of orange juice, 1 tablespoon of the agave, and nutmeg.
Bring the mixture to a boil, then reduce the heat to a simmer and allow the apricots to break down some, 4 to 5 minutes. It should be chunky, but not have large pieces of fruit.
In a small bowl, combine the remaining 2 tablespoons of orange juice and the cornstarch.
Add to the mixture and stir until thickened, 3 to 4 minutes.
Taste and add the remaining 1 tablespoon agave if needed.
The jam thickens as it cools, so make it ahead of time and refrigerate in an airtight container until you're ready to use it.