What is the meaning of なる?

to be achieved; to be completed

to become; to change into; to turn

to reach a time; to get to a timepoint

to reach an amount/quantity

to be acceptable; to be tolerable

to be made; to be produced; to be created

to promote

In the form of "()/() + verbal noun + なる", an honorific form of the verb.

adnominal of なり (nari, to be)

Source: wiktionary.org