Stir the berries and chia seeds together in a saucepan.
Simmer, covered with a lid, for 5-10 minutes, until softened. Add 1 Tbsp of water to loosen the jam if it seems too thick.
Gently mash with a fork to your desired smoothness.
Transfer to a jar or lidded container and enjoy warm or refrigerate. Keep in mind that it will continue to thicken up in the refrigerator, so if you eat it right away it will be runnier, but still perfectly yummy! If you refrigerate it, it will set and become more of a jam-like consistency.