In a regulated mod, the battery never "sees" the resistance of the coil. You set the wattage, the DC to DC converter provides the current to the coil. To calculate load you need to use Watts law. A=W/V.
So to calculate how many amps you will draw for a given wattage, you divide watts by the cutoff voltage of the cell, usually ~3.2V for the average mod (yes, you start higher in a fully charged battery, but the goal is safety here, and the max draw will occur at the lowest voltage you will discharge to with use). Subtract another 10% of efficiency of the board (that's an average, boards are different, some more efficient than others but that's a safe bet).
So let's say you chose 60W. 60W/3.2V=18.75A/.9 (efficiency)=20.9 A. So with a 20A battery like the 30Q you're good, under average circumstances, to about a 60W draw under normal operating conditions.
Getting back to your setup. On a Pico you would run that 0.15 ohm Ni coil in Ni temp mode. You would select the temperature you want. You can also select the maximum wattage you want to "allow" the mod to use to reach that temperature. You can set that wattage (say 30W) and watch whether the mod hits the target temperature (say 450F). If you see it get close to 450F, or you see a screen "temp protected", your mod is then regulating that wattage to maintain the set temperature for you. All's good, providing you've got a good vape you're enjoying. If not, adjust your temp up or down accordingly.
