Peel the pineapple and chop it up, the hard inside can also be used. Stone and chop the nectarines as well. The bowl can stay on.
Puree the fruits and place in a sufficiently large saucepan. Mix with the preserving sugar and cook according to the instructions on the sugar packet. The nectarine peel boils over completely and the jam takes on a nice color.
After the cooking process, pour the jam into boiling hot water jars and screw on immediately.