We had 2 ants nests last year, one by the patio doors and one in the wall of the house.
I put down two little round tubs of ant killer that I brought from Wilkinsons(can`t remember what it was called but the tubs were red and they had a big ant on the top). The ants crawl inside get stuff on their feet and trample it back to the nest. I put a brick on the top of each one so the dogs wouldn`t eat them and this year no ants.