I believe full vaccine and a negative nasal swab is pretty much zero risk.
The worry about vaccinated people spreading the virus is that some vaccines don't give mucosal immunity - which means the virus can live on your mucous membranes and only gets wiped out when it tries to cross that into your bloodstream, but while its on the outside, coughing, sneezing etc. can still spread it.
The nasal swab tests the mucous membrane in your nose, so if you are fully vaccinated and you test negative in a nasal swab, unless you get a false negative (which are really rare), there's nowhere for the virus to be.