My nephew is positive for covid. i caught covid in august, am i likely to get infected again? i did not receive the bivalent vaccine?

Certainly you are susceptible to a new covid infection. But it is impossible to judge the likelihood without information about the nature and frequency of contact with your nephew.

Newer variants are extremely contagious, however milder forms, mild cold-like symptoms for vaccinated and natural immunity ( individuals that had the infection recently). Hard to estimate risk of acquiring in exposed individuals, a variety of physical and chemical unknowns apply.