The H2020 project Nature4Cities conceived a NBS typology thought to be easily accessible even to non-specialists and developped a "NBS explorer" where users are free to stroll around NBS.
There you can watch pictures, see all the challenges that a NBS is addressing, and conversely, all the NBS addressing a particular challenge. You can also see at which scale the NBS is developed and download an extended factsheet giving a whole raft of details on the NBS.