noise analysis spice
As said by gunturikishore, if you want to calculate the NF, you need to use a "port" instead of the standard "vsin". NF can simply be seen as the noise your circuit add to the noise from previous stages. Vsin source don't generate any noise, whereas with a port you must specify the resistance value, which will generate some noise.Then you should be able to plot the NF.
As for noise simulation itself, I think it's not possible in transient (maybe you could find more details in a Spice book). In my understanding, noise model are not random sources, but equivalent fixed current or voltage source, whose value are fixed by the circuit operating point, and also the frequency. So that's why you perform the AC analisys. Also noise is expressed as nv/√Hz and then integrated over the BW to get the rms. So you kind of need the AC sweep somewhere.
I hope it helps a little