It is a word borrowed from Spanish, according to merriam-webster. Therefore, the plural will be nutrias according to the rules of Spanish. All those other words, though probably latin or Greek in origin, have been in the English language long enough that they are no longer borrowed words and therefore follow English grammar rules.

Like pearls to swine is a very seldom used idiom in English too, used very rarely and often in archaic/medievel/fantasy settings. Very interesting 2 languages have a shared idiom so neatly translated.

Work boots? Try Thorogoods, redwings, even a few of the Wolverines brands like Bates are awesome.

Casual wear boots are somewhat trickier. Gotta just try em on in person see which ones fit to you correctly.

There is a “break in” period for all leather boots though, where the leather softens at the natural bends when you walk. Takes only a few days if you treat the leather right and keep it clean and moisturized.