НАДО - we can`t use with nowns. It is very inelegant and clumsy for russian lenguage. We can`t say " Мне надо машину или Нам надо работу". Russian people speak : " Мне НУЖНА машина или Нам НУЖНА работа". The word : Нужен/нужна/нужно we can use with nowns and verbs. For examples: " Нам нужно работать (verb) или нам нужна работа (noun).". But I remember an exception to the rule for a friendly dialogue when : first friend asks - ЧТО ТЕБЕ НАДО ? // second friend answers - ШОКОЛАДА ! It`s a comic answer for a rhyme of НАДО to a word ШОКОЛАДА that the second friend should conceal the true sense of his bothering. The answer-ШОКОЛАДА is the same НИЧЕГО

НАДО/НУЖЕН/НУЖНО it is necessary - if something you require or something is necessary to make for examples: to me it is necessary many euro I need to read through the book не нужно/it is not necessary - it is not required actions (nothing is necessary) for exemple - It is not necessary to write the letter