Could just the influx in hormones... In the beginning of any cycle your hormones start to sky rocket so your body is trying to adapt to everything we're doing(AI hcg test etc)
And in my experience puffy nips are normal - not so much if they hurt - sensitive nips can also be from shaving and the fabric rubbing against them etc
Do they feel sore, & is they're any type of lump behind the nipple? Don't play w/them - but if Ya can find out if a lil lump is forming(if so start Nolva at 20mgs ed then back it to 10mgs ed until gone) How long have you been on? That's a pretty good dose

so I'd def watch(get BW for dex and DA adjustments