I missed my Isha because that time I was traveling, but around 11:30 pm I reached my house. Do I have to pray 2 Raka'h or 4?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

Know, dear brother, that the Islamic ruling concerning the traveling person terminates as soon as he enters his place of residence.

So, any prayer the person performs in that place and at its prescribed fixed time, he should pray it in full length; i.e., he is not supposed to shorten it. The reason for this is because he is now a resident not a traveler.

For more benefit on the ruling on shortening and combining the prayers, please refer to Fataawa 362857, 83821, 90615, 90113, 88402 and 350368.

Allah knows best.