Don't assume that a word that has been borrowed from another language will retain its meaning, pronunciation, or grammatical function in English.
The word visa, in English is a singular countable noun, and the plural is "visas"
(The etymology is that visa is short for "charta visa" = document that has been seen. "visa" is the of the nominative feminine singular of the perfect passive participle of videō, so not a plural at all, not not a noun either. Quota comes from a shortening of quota pars, and is the nominative feminine singular. Again, not plural, not even a noun)
[You might have a better case with "data", which is a Latin plural noun, but usually treated as singular uncountable in English, although "datum" is occasionally used. As an observation, in English maths tests for all students at age 16, "data" is treated as singular: "this data". In advanced level tests for students at 18 it treated as plural. I doubt that many students even notice.]
[Further case, while I'm on the subject: "referenda" is a hypercorrection of the correct "referendums" since there is no Latin plural of the gerund referendum. But it is common enough that it can be accepted as an irregular plural.]