Lenin was embalmed, mummified, cooled, and placed in a sterile environment by scientists dedicated to preserving his corpse. This nun was put in a plain pine box and buried in a field. Not exactly comparable.
Comparable in terms of creepiness.
Every now and then they’ll come across an ancient body in the bogs of Britain, tannin contained in the peat almost perfectly preserves the features.
Perhaps the pine box combined with tannins in the soil influenced the natural preservation.
Corpse worship, just the same.