Is it possible for human beings to feed through the nose?
Certain vitamins, for example, vitamin B12, can be absorbed through the nasal mucosa by simple diffusion.

Many nutrients can be absorbed through the intestinal mucosa only by the help of specific carriers. These carriers are not likely present in nasal mucosa, so the nutrients in question may not be absorbed there.

The other problem, especially with macronutrients (carbs, proteins, fats), is if the surface area of nasal mucosa is big enough to absorb large amounts of macronutrients (carbs, proteins, fats) needed to meet nutritional demands. In one experiment, only 0.1 mg of glucose from a given dose was absorbed through the oral mucosa.

In another experiment, some amino acids were absorbed from oral mucosa.