* Necesitamos: This is the most common and general translation. It's used in most situations where you need something.
* Tenemos que: This translates to "we have to" and is used when there's a necessity or obligation.
* Nos hace falta: This translates to "we need/lack" and implies a need for something specific.
Examples:
* Necesitamos más tiempo. (We need more time.)
* Tenemos que ir al supermercado. (We have to go to the supermarket.)
* Nos hace falta un coche nuevo. (We need a new car.)
Choose the translation that best fits the context of your sentence.