BrE and AmE pronunciations of Nokia, rendered as KNOCK-ee-ah and KNOW-kee-ah, respectively.
…the single consonant should signal an /o/ in my spelling world, so why the 'knock' vowel?
It’s true: in Britain we (all?) say ˈnɒkiə, with the LOT vowel, whereas Americans say ˈnoʊkiə, with the GOAT vowel. And it’s also true that the spelling o, when followed by a single consonant plus ia, otherwise corresponds to GOAT: phobia, Cambodia, magnolia, begonia, utopia, ambrosia, Scotia. (OK, anoxia is an exception, but x is pronounced as two consonant sounds, not one.) So the BrE pronunciation of Nokia does seem to be exceptional from a spelling-to-sound point of view.
(The rule in question does not apply to all vowel letters in this context: cf. Lydia, familiar, Abyssinia etc., with short ɪ. In bulimia we get not only ɪ but also unexpectedly iː. The same is true of memorabilia.)
It seems far-fetched to imagine any influence from gnocchi ˈn(j)ɒki. Anyhow, I believe Americans mostly say ˈnɑki if they know the word at all.
There is, however, a parallel in yog(h)urt, which is ˈjɒɡət in BrE but ˈjoʊɡɚt in AmE, and it may be relevant that in BrE we are happy to map ‘foreign’ o onto our rounded LOT, ɒ, whereas Americans are less ready to map it onto their corresponding unrounded and therefore phonetically more distant ɑ. However this plausible line of reasoning falls down when we consider the Australians, who use their GOAT vowel in yoghurt despite having a LOT vowel that is rounded, just as in BrE. (The word comes from Turkish yoğurt joˈuɾt.)
I don’t know what Australians do with Nokia.
In Finnish it’s ˈnokia, just as written. Finnish has contrastive vowel length, and these vowels are short. The company is named after a town near Tampere.