expression, godan verb (-su)
to love one's child too much for their own good; to love one's daughter so much as to make her a nun
Rare, literary idiomatic expression. Literally 'to love so much that one makes (her) a nun', implying excessive parental affection that leads to an undesirable outcome. The literal gloss refers to a historical practice of making a beloved daughter a nun, but the phrase is used more broadly for overindulgence.
The phrase '寵愛昂じて尼になす' means to love one's child so excessively that it brings misfortune instead.