Boil water in a kettle; you will need 1 cup of boiling water to dissolve the jello.

Lightly coat a jello mold with baking spray and set aside.

Strain the mandarin oranges, reserving the liquid; add water if necessary to reach ¾ cup.

Pour 1 cup boiling water over the orange jello mix and whisk until fully dissolved.

Add the reserved mandarin liquid and ½ cup cool water, mixing to combine.

Stir in ½ cup sweetened condensed milk until fully incorporated.

Pour gelatin into the prepared mold and top with the mandarin orange segments.

Refrigerate jello until firm, about 4 hours.

To un-mold, dip the mold in warm water for 15-20 seconds, then invert onto a plate or serving platter.

Serve the jello salad in slices.