In the pot of your instant pot or in a stock pot for use on the stovetop (choose a large one, it will bubble up in later steps), combine sugar, coconut nectar, cream, and sea salt with a whisk, until all sugar is wet. Clip on a candy thermometer so that the bulb is in the syrup but not touching the bottom of the pot, and turn the Instant Pot on to Saute-Medium. Alternatively, heat pan on the stovetop over medium heat.
Heat sugar mixture to soft ball stage (235* F) without stirring.
As the sugar mixture heats, prepare loaf pan by lining with parchment paper,so the parchment goes all the way up the sides of the loaf pan.
Once the syrup is at soft ball stage, remove from heat and stir in almond butter and vanilla.
Pour fudge into prepared loaf pan. Gently shake the loaf pan if needed to smooth the mixture into the corners.
Allow nut butter fudge to cool at room temperature, then cut into cubes.
Store in an airtight container between parchment for up to 3 weeks.