I had a chance to look at a couple of old Thom's today and I see a listing for a John Nixon, grocer and vintner, at 80 Upr Dorset Street in 1885(ish) and 1890 but not 1895.
Shane do you have any Thom's for early 1890s? Might be interesting to see what year the listing disappeared. Could be a son of John senior of course. I can't actually see any death of a John Nixon in Dublin North in the early 1890s.