Research into the negative or positive health effects of nasal snuff tobacco seem to be quite thin on the ground, largely due to its decrease in popularity over the past century. Most reports just place all smokeless tobacco products into one category, which includes dipping tobacco, chewing tobacco and snus, so it is difficult to make any firm judgement on the subject.

So to help you make up your own mind I have searched the web for all relevant articles that I could find that refer as much as possible to nasal snuff tobacco:

Smokeless New Zealand
Most recent report on the benefits of using nasal snuff tobacco to give up smoking.
Includes:

• Is quitting smoking entirely, better than switching to snuff?
• Comparing cigarettes, snuff and nicotine for quelling the urge to smoke
• Nasal snuff - chemical analyses
• Snuffing linked with lower overall cancer rates than smoking at the main sites of tobacco use

British Medical Journal
1981 report from the British Medical Journal on 'Nicotine Uptake by Snuff Users

Cambridge Journals
"Although it contains substances that are potentially carcinogenic, at present, there is no firm evidence, relating the use of nasal snuff to a higher incidence of head and neck or other malignancies."