Green’s Dictionary of Slang

(US) affected, prissy.

1930		W.R. Burnett Iron Man 228: This little kid here with all her nicey-nice talk.
1971		D. Athas Entering Ephesus 111: People had been too polite and nicey-nice to seat them-selves in these prominent chairs.
1980		W.A. Swanberg Whitney Father, Whitney Heiress 349: Dorothy was the soul of propriety in things nonpolitical, possibly too nicey-nice for Gertrude.
2004		A. Krach Half-Life 294: Why don’t you quit this nicey-nice bullshit and just say whatever it is you want to say and get it over with?
2020		A. Parks Bobby March Will Live Forever 311: ‘Enough of this nicey-nicey pish,’ he said. ‘Drink up and let’s [...] [g]et pissed, properly pissed’.