Interchangeable with "look" in the same way as "nose" is - i.e. "I'll have a look" or "I'll have a nose" or "I'll have a snout".
Typically used for food-related items but can be used anywhere "take a look" is appropriate. Obviously a slang term and not to be used in school work or in a professional capacity.
Have a snout at the menu, it's not bad.
I didn't know they made those too, I'll have a snout.