Green’s Dictionary of Slang

nutty adj.2

[nuts adj.]

1. [19C+] very fond of, obsessed with, amorous.

2. [late 19C+] (orig. US) crazy, eccentric; esp. in punning phr. nutty as a fruit cake, nutty as a peach orchard boar.

In compounds

nutty house (n.) [var. on nut house n. (2)]

[1910s] (US) a psychiatric institution.

In phrases

nutty about (adj.) (also nutty for) [sense 1 above; heavily influenced by sense 2 above, on model of SE phr. crazy about]

[1910s+] (orig. US) fond of, keen on.

nutty upon (adj.) (also nutty on)

[19C] amorous, fond of, obsessed by.