Yes. I've just bought sodium nitrate and will be making it into sodium nitrite, and write a guide on it (Coming out within the next 10 days). Here's the plan if you want to try:
Materials
Sodium Nitrate
Aluminium
Method
1. Heat up sodium nitrate and some aluminium (<300C, or the sodium nitrite would instantly decompose)
2. Wait until all the aluminium oxidizes to become aluminium oxide
3. Add more aluminium if all of it oxidizes. Repeat until the aluminium no longer oxidizes. (Takes possibly 1hr)
3.5 Cool it down
4. Add purified water (distilled)
5. Stir and dissolve the powders
6. Use some sort of filter paper (coffee filter paper is good enough generally)
7. Let the water evaporate. DO NOT use heat over 300C!
8. Repeat step one to seven as many times as you need, until newly added aluminium to just the powder no longer oxidizes
9. Dissolve and filter once or twice more
10. Done! In theory, you should now have sodium nitrite! I would test it before using it though.
If you can't do this method, let me know. I have some more that you can try.