You can go to the store and buy chemical filled vegan condensed milk.  We choose to make our own, and as you know we make our own nut milks.  

What you will need:

3 cups/750ml/729g soy, OR rice, Or other vegan milk
1/2 cup/100g sugar (for more nutrients, use evaporated cane sugar)
1/2 teaspoon vanilla extract
salt

This is what you do:

Mix your “milk” and sugar in a saucepan and cook over medium heat stirring constantly.
You will stir until reduced by half.  Remove from heat.  Add your vanilla and a pinch of salt and mix well.Cool before using.