So, when it goes for nicknames, something like "misiaczku" or "koteczku" will do. For Prussia I would go with "kurczaczku" (it means "little chicken") or "prusaczku"(this is kind of joke, since "prusak" is a kind of bug and German/Prussian soliders where called "Prusaki" in Poland). But, these forms you can use when addresed to a specific person - if you want to use these nicknames in a dialogue with someone else(while talkig about Prussia), you should use "misiaczek", "koteczek", "kurczaczek" and "prusaczek". It's a matter of form, meaning is exactly the same.
'I love you' - "Kocham Cię" 'walnuts' - well, it can be difficult, since the phrase 'I feel lika walnuts' can't be translated directly into Polish. Literally it would mean "orzechy"(but I don't think you mean this...) or "jądra", if you mean testicles. Still, it sounds a little odd in Polish ^^'' 'Feel it' - "Poczuj to" 'See?' - "Widzisz?"
Re: Polish help
So, when it goes for nicknames, something like "misiaczku" or "koteczku" will do. For Prussia I would go with "kurczaczku" (it means "little chicken") or "prusaczku"(this is kind of joke, since "prusak" is a kind of bug and German/Prussian soliders where called "Prusaki" in Poland). But, these forms you can use when addresed to a specific person - if you want to use these nicknames in a dialogue with someone else(while talkig about Prussia), you should use "misiaczek", "koteczek", "kurczaczek" and "prusaczek". It's a matter of form, meaning is exactly the same.
'I love you' - "Kocham Cię"
'walnuts' - well, it can be difficult, since the phrase 'I feel lika walnuts' can't be translated directly into Polish. Literally it would mean "orzechy"(but I don't think you mean this...) or "jądra", if you mean testicles. Still, it sounds a little odd in Polish ^^''
'Feel it' - "Poczuj to"
'See?' - "Widzisz?"
Hope it helps you :D