BrainGlobe has a new atlas, the "CCFv3 augmented mouse atlas"!
This atlas is an extended version of the CCFv3, designed to cover the rostral and caudal tips of the mouse brain and includes Nissl templates.
More details: https://brainglobe.info/blog/CCFv3BBP.html
Original paper: https://doi.org/10.1162/imag_a_00565