Evap leak at top of fuel pump question.

[Gbh]

I found my evap major leak with a smoke test. It’s this nipple- looking thing in the picture that is unused. A mouse made a home on top of my fuel tank and as best that I can tell, the mouse ate into this and now it is leaking. If I cap it, evap pressure holds as it should.

I just want to verify that sealing it off is OK.

Thanks for any input.
Greg
2014 S60 T5 AWD