Hi Terry, welcome to Healingwell.
I've got no personal experience with the nasal sprays myself as I use sublingual tablets, but I can tell you that the idea is medically sound - in effect it is using the moist membranes in the nasal cavity as mucous membranes, which is exactly what they are, and into which the right molecules will simply dissolve.
The other form of B12 available to those who cannot have injections (ie all us UK Crohnies who need to have it prescribed, with docs that almost always consider it unnecessary) is the one I use - sublingual. Same idea as the tablets for angina that dissolve under your tongue into the bloodstream, available from health stores. As part of a host of other blood tests I had my B12 levels checked recently and they were fine, whereas previously I had clinical symptoms of deficiency, and if anything my gut would be less effective recently at absorbing B12 via the oral route, so I am pretty sure that it is the tablets that have made a difference.
I use Solgar, if that is any help to you, but I am sure there are lots of different brands out there, it is a common byproduct of the brewing industry.
Hope that helps.