Trying to install nasm-2.1108 but getting permission deny
User-provided binaries should get installed to /usr/local/ (or more specifically /usr/local/bin) to avoid any versioning conflicts with standard applications/binaries. There should be an option to set the install directory to /usr/local when you run ./configure in your build directory.

PS: In OS X before El Capitan, it was rather easy to install to /usr/bin nevertheless. With El Capitan, Apple has introduced SIP to prevent these kind of modifications. There are ways to disable SIP, but I recommend to install to /usr/local instead.