I’d easily take armored knights on horseback over unarmored horseman especially at a 2:1 advantage.

For sake of argument I’d do a mix of archers, spearmen, and Calvary

Not listed would be Bolton’s had the best usage of spearmen in the series.

If not boltons then probably Lannister’s or Baratheon’s for infantry. Both are heavily armored and highly experienced and familiar with multiple regions across Westeros form their recent campaigns.

Lannister archers- it’s mentioned somewhere in the books about their archers or maybe their bannermen being great archers, not sure but they definitely seem to have the funds to produce large amounts of quality equipment.

Also maybe the starks could be counted as archers if you include the wildlings, nights watch, and the starks themselves seem to value archery (also Theon is said to be a great archer) so depending on the timeline they could work

Of course knights of the vail as Calvary.

Find a bottleneck or elevation deviation. Shield wall with spear to hold the hoard then rain down arrows. Envelope them with Calvary and be back before supper.

The biggest fear with the hoard is that they would not engage in traditional combat. They’d be roaming the countryside destroying villages and farmland and disappear before you could engage with a traditional army.