This is what a Nosler Ballistic Tip looks like sectioned. You can see the solid base design:

Originally Nosler made Partition bullets. Then they added their cheaper Solid Base line. Those were constructed just like this except they had no plastic tip - just a standard lead tip. Next they came up with the first plastic-tipped bullet - the Ballistic Tip. It was a HP version of their Solid Base except for there being the polymer tip inserted into the HP that kept the BC higher (less damage in the mag under recoil) and initiated expansion. They also garnered a rep for being a very accurate hunting bullet.
Eventually the Solid Base line of lead-tipped bullets using this jacket design was discontinued in favor of the Ballistic Tip version. Winchester loads them and calls them Ballistic Silver Tips.
They tended to be a little ‘soft’ on big game in most calibers but over the years Nosler has tweaked them a bit. The final tweak is a core-bonding process that locks the core to the jacket in what is basically a Ballistic Tip and are sold as Accu-Bond bullets. Nosler has engineered them to expand in a controlled fashion to about the same extent as a Partition. They are also available in Winchester Supreme hunting ammo - AccuBond CT. BC is usually higher than the same weight/caliber Partition.
I hope this clears up any confusion from my previous posts.