Since you've already reached full retirement age for social security, there won't be any benefit reduction due to the amount of earned income you receive. So that's good news.
As you already know, social Security benefits (with the exception
of SSI) are taxable, but with limitations. Those limitations depend on
the amount of additional income you receive. The amount of your social
security that's subject to tax can change from year to year, from zero up to
85%. So when you return to the workforce, that additional income will be factored into this determination.
It could be that, based on your retirement and other income, the 85% max social security amount was already subject to tax. If so, this additional income won't change anything in that regard. If your taxable amount was below the 85% max, then it's quite possible this new income will boost you up to the maximum. That's something to anticipate.
In addition, as with taxpayers of all ages, as you receive more income, there's the possibility that you will be elevated into a higher tax bracket, so you'll want to adjust your withholding accordingly. Perhaps, if you aren't already, you might consider having taxes (or an increased percentage of taxes) withheld from social security and/or your retirement income.
Here's a link to IRS Publication 915 which discusses all
aspects of social security (see the heading How much is taxable on page
6): https://www.irs.gov/pub/irs-pdf/p915.pdf
