* Exasperation or frustration: Think of someone throwing up their hands in exasperation, saying "Ah, chestnuts!" after a particularly annoying or difficult situation.
* Disappointment or resignation: "Ah, chestnuts!" could be used to acknowledge a situation that is not ideal but ultimately unavoidable.
* A bit of humor: It might be a way to add a touch of levity to a situation.
However, without context, it's impossible to definitively say what the intended meaning is.
If you have more context or the full sentence where "argh chestnuts" appears, I might be able to give you a more accurate interpretation.