No, you just need a copy on your computer since NSC_Builder is a computer program not a homebrew application. You will also need a set of Switch keys which can be obtained legally with Lockpick.
Hold up, you're telling me I can download a pirated copy of Astrol Chains now and then without even having a cartridge side load it to a micro sd card and play it on a Switch with an upgraded version to the games required version using ChoiDojourNX?