Can I name my son [name_m]Luke[/name_m] and call him [name_m]Louie[/name_m] as a nickname?
I think it’s a bit of a stretch.
It kind of makes sense…[name_m]Luke[/name_m]> Lukie> [name_m]Louie[/name_m]…and you could easily justify it even from the “loo” sound in [name_m]Luke[/name_m]. It just doesn’t scream nickname to me because nicknames are typically shortened versions of a name and [name_m]Louie[/name_m] is a whole syllable longer than [name_m]Luke[/name_m]. Regardless, if it is important to you, then sure.
I like it!
Sure! We have a [name_m]Luke[/name_m] and we call him Lukey sometimes. I think [name_m]Louie[/name_m] is a natural extension of that. My husband’s sister lengthens all their kids’ names for nicknames, instead of shortening them. My youngest sister is [name_f]Eliza[/name_f], and she had so many nicknames I can’t even count them. It started with [name_f]Eliza[/name_f] [name_u]Lou[/name_u] (which is not her middle name), then went to [name_u]Lou[/name_u] [name_u]Lou[/name_u], [name_u]Lou[/name_u], and somehow [name_f]Fifi[/name_f] and Feef, plus others. Nicknames are malleable and ripe for creativity, and [name_m]Louie[/name_m] is not even that much of a stretch from [name_m]Luke[/name_m].
I think it works fine. [name_m]Luke[/name_m] could easily become [name_u]Lou[/name_u], which could easily become [name_m]Louie[/name_m].
[name_m]Louie[/name_m] is a name name so I would go straight to it rather than the confusion of him being called by a name that most people would assume is his name. [name_m]Just[/name_m] name him [name_m]Louie[/name_m].
You can, but I would name him [name_m]Louie[/name_m].
Exactly! It works for me 
Yeah it makes sense!
Makes perfect sense. [name_u]Lou[/name_u] is the first syllable of [name_m]Luke[/name_m]. Not a stretch at all.
Nicknames come from lots of places. My daughter [name_f]Betsy[/name_f] is called [name_f]Lulu[/name_f] all the time (from her middle name), but we also call her Bug and Buggy (I don’t even remember how that started).
100% yes! [name_m]Benjamin[/name_m] can be called [name_m]Benji[/name_m] or [name_m]Benny[/name_m]. [name_m]Just[/name_m] because [name_m]Louie[/name_m] is already an established name doesn’t mean it can’t also be a nickname. 