If you are talking about creating a Resource Pack to change the Chisel and Bits assets, then it's possible. Pretty much anything in the assets folder can be changed by a Resource Pack. The only block in the mod is the Bit Tank, which has a rather complicated model that references vanilla textures, but that model is in the assets folder so you can change it to use your own textures if you wanted to. Of course, if you are asking if you can use Chisels and Bits to cover up other blocks then the answer is sorta? Some properties, like light level, are dependent on how many of those bits are in the final block, so you can make hidden lighting by taking a Glowstone Block, removing a plane from each visible side that is only 1 bit deep, and replace it with another block's bits. On the other hand, if you want to cover up blocks that can't be chiseled themselves then you will need to hope they added special support for MCMultiPart (because of bugs and relying on an external API that is really rare), or your best alternative is a 1 pixel cover in the adjacent block spaces (making your block bigger than 1 block, or 18 pixels big). More on reddit.com

Could the chisel 2 team please release a upscale 32 and 64X resource pack. when using Chisel 2 with any HD textures the difference in resolution creates a obvious clash between Chisel blocks and va... More on github.com

You can find the changes over at the Imgur Album, or you can try the changes yourself with this Resource Pack! ... TL;DR Chisel is getting new textures, I would love feedback on these changes. More on reddit.com

bits just use a small portion of the full block's texture. the only way to do that without another mod to change that would be making every texture itself repeated in a 16x16 grid, and that's probably not what you want More on reddit.com