Astral Heron and Whiteflame with Nasus Legend

So as i read the Nasus legend it doesnt say i need to spent 7 like for example Jhin wo wants to spend 4 energy.

So if Heron is at a BF and i hold, kann i play a card and then play Whtieflame for 6 because of the Reduction but still trigger Nasus cause i played a Unit with Energy colt 7 or Higher?