Unreal Engine 4.21 has just released, and it includes some tweaks that are specific to the Switch. Check out a snippet below, and then hit up the link for the full patch notes.
Niagara Platform Support and Usability Improvements
In our continuing effort to provide industry-leading effects tools, Niagara has received an expanded feature set, substantial quality of life improvements, and Niagara effects are now supported on Nintendo Switch!