This is the one I bought for mine. It fits.

2-Pack CR10 Z axis T8 Anti Backlash Spring Loaded Nut Elimination Gap Brass Nuts for Upgrade Ender 3 Ender 3s Ender 3 Pro V2 CR-10 Tornado 3D Printer 8mm Acme Threaded Rod https://www.amazon.com/dp/B08LZ1V56T/ref=cm_sw_r_apan_i_1VVQ66AYTQY2Z6PDC5NA?_encoding=UTF8&psc=1

I replaced the couplings with Oldham Couplings + Anti-Backlash nuts.