Thanks GoobGuntz and kamitani_08 for helping me figure this out! NiagaraFunctionLirary.h allowed me to spawn Niagara effects, and you have to put “Niagara” in the build.cs file. I was able to spawn a system like this:
UNiagaraFunctionLibrary::SpawnSystemAtLocation(GetWorld(), SpawnEffect, MeshComp->GetComponentLocation(), MeshComp->GetComponentRotation());