You can use the word "cocktails".
'nuts' has a couple of meanings, 'nuts' are the things that you have in an aperitif, but it's also a way of calling somebody a crazy person, you say 'You're a nut!', means 'You're crazy!
In my opinion yes, it is, but a more common way (and a formal one) to say this is: don't hesitate TO CONTACT me
You may say "haudi" which is a funny slang import of the English word. More common way to say it is "moro" or "tere" or "tervehdys(not spoken language anymore)".
In Brazil, the most common way to say goodbye is "Tchau." Another informal way to say goodbye is "Adeus." In more formal situations, you can say "Até logo" (See you later) or "Até breve" (See you soon).
とんでもない (tondemonai) is a common way to say "no way" in Japanese.
not common or rarely
Although it's not mormally said that way, it would be "quince cientos." I believe it would be more common to say "mil quinientos."
"gut" is the most common way to say "good" in German.gutbravartiglieb
In Haiti, the common way to say "welcome" is "Bienvenu".
'Jinsei wa tsumaranai desu' is a common formal way to say "life is boring" in Japanese. A common, yet informal way to say this would be 'jinsei nante tsumarani'.
nargis
Sayonara is the most common way.