A good starting point for NEIPA is:
78-85% Golden Promise
15-20% Flaked Adjunct (any combination of Flaked Oats/Wheat/Barley)
0-2% Honey Malt
Gravity around 1.060. Increase or decrease to taste. Bitter with a small amount of high alpha hops, then all other hops added at flameout, in whirlpool, and dry hop. This grain bill is a very good base for testing different types of hops.
Edit: You could also use Pilsner or 2-Row (I prefer Weyermann or Rahr for these), Fawcett Pearl, Maris Otter, or any combination of those in place of those in place of Golden Promise. Golden Promise is definitely one of the favorite base malts used in NEIPA's right now though.