Slice your nectarines in ½ inch slices and place in a large bowl.
Toss with sugar and lemon juice until well coated and the sugar is completely moistened.
Allow the nectarine mixture to sit at room temperature for 2 hours, tossing halfway through.
After 2 hours, strain the nectarine syrup from the nectarine solids using a fine mesh strainer. Allow the mixture to strain for about 30 minutes, tossing halfway through to get the most syrup. Reserve the syrup, discard or save the nectarines for another use.
Transfer the nectarine syrup to an airtight container or syrup bottle, and store in the fridge for up to 7 days.