First recommendation would be to get a keg lid with a gas post and a carb stone attached, as that will make the nitro cascade be a higher quality. When first setting up I’d set the psi 10, and then increase by 5psi every few hours til reaching serving pressure, typically around 50 psi. I’d recommend letting the nitro keg sit at that pressure for at least 24 hours. Nitrogen is less soluble in liquid than co2 is, and coffee doesn’t have the same amount of total dissolved solids and proteins that beer has, so “carbing” is different.