NuggetSaver.cs

void Main()
{
	var n = new NuggetSaver(7,11);

	(n.OrderNuggets(20) == (3, 0)).Dump();
	(n.OrderNuggets(100) == (8, 4)).Dump();
	(n.OrderNuggets(-20) == (0, 0)).Dump();
}

class NuggetSaver
{
	public int Size1 { get; private set; }
	public int Size2 { get; private set; }
	
	public NuggetSaver(int size1, int size2)
	{
		Size1 = size1;
		Size2 = size2;
	}
	
	public (int order1, int order2) OrderNuggets(int count) {
		int minWasted = int.MaxValue;
		int order1 = 0;
		int order2 = 0;
		int maxOrder1 = (count % Size1) > 0 ? count / Size1 + 1 : count / Size1;
		int maxOrder2 = (count % Size2) > 0 ? count / Size2 + 1 : count / Size2;
		
		for (int o1 = 0; o1 <= maxOrder1; o1++) {
			for (int o2 = 0; o2 <=maxOrder2; o2++) {
				int waste = count - (o1 * Size1) - (o2 * Size2);
				if (waste <= 0) {
					int absWaste = Math.Abs(waste);
					if (absWaste < minWasted)
					{
						$"{o1}, {o2} = {absWaste}".Dump();
						minWasted = absWaste;
						order1 = o1;
						order2 = o2;
					}
				}
			}
		}
		return (order1, order2);
	}
}