Snorting kratom won't work, it will destroy your nose and lungs though. The consistency of micronized kratom is almost dust-like and will shoot straight into your lungs and induce a serious coughing/sneezing fit, perhapse even some sort of lung infection if you're unlucky. I would recommend ruling out whether it's the plant matter or the drug that's causing your nausea.
Make a tea and if you're still nauseous you will know that even if plain leaf kratom were active intranasaly it wouldn't solve you're problem. Especially taking into consideration that you're still going to end up ingesting the plant matter once it drips. Usually a dose adjustment is necessary when you get nausea. People regularly try and surpass kratom's ceiling by dosing too high.