In case we do not have time to make nut milk at home, is there a trustable brand that we can get it from?

If the nut milk is natural, it will go bad in 2-3 days. It cannot be preserved for long unless a preservative is added to it. Most packaged nut milks have preservatives and chemicals added to it. 

However, in times of emergency (when you have no other option available), you can opt for coconut milk powder from a reliable source.