A couple of things to consider here.
*BTUs: If you overload your pan you may not obtain the heat you require, depending on your stove's output capability and the actual dish you intend to make. In this case several smaller quantities may be preferable.
*Spicing for increased quantity: I read somewhere that for a "recipe stipulated spice list", each doubling of overall quantity only requires an increase in spices of 50%; ie, not double the amount as you'd expect. So for example, if a written recipe calls for 500g of chicken and 1 tsp of any spice, let's say cumin, then if you double the amount of chicken to 1 kg you only increase the cumin to 1.5 tsp, (not 2). The same would apply for all other spices.
Disclaimer: I think this is correct, but I'm not sure of it as a fact and haven't tested it, so don't take my word for it. Perhaps others may comment as to this "general rule's" validity.