We should totes break the entire internet and violate civil and human rights of everyone over the intentional misuse of pickling spices by individuals, bros.
You can OD on sodium nitrite from eating too much bacon or drinking too much wine that used it as a preservative. And I'm not even talking about where someone screwed up the measurements and used way more SN than is generally recognized as safe, but just people eating regular SN preserved food and drink in excess and I guess attributing any odd feelings they developed as being meat sweats or unpleasantly like being drunk and kept powering through.
Sodium nitrite works as a chemical asphixiant, which isn't necessarily as fun as simple physical asphixiants (e.g., inert gases) since they can interfere with CO2 transport.
This would not lead to feelings of suffocation, though, but probably feel more like acidosis.
You will probably not experience hypoxic euphoria, but also probably not have a "this will kill you and it will hurt the entire time you're dying" experience, either. You'll probably feel a little nauseous and generally uncomfortable, like exercising too hard on a hot day while already dehydrated, before losing consciousness due to hypoxia.
There are dozens of ways you could choose to poison yourself found at the nearest supermarket, with many of these substances, like sodium nitrite, in the grocery aisles. Where they belong.