Hello again @ptcaos ,
Does not have plans of add an option to create an assembly project in MCUxpresso.
On the other hand, in order to start with the FRDM-MCXA153 you can consult these references that could be helps:
Also, MCUxpresso IDE provides an SDK, where is a comprehensive software enablement package designed to simplify and accelerate application development with Arm® Cortex®-M-based devices from NXP, including its general purpose, crossover and wireless-enabled MCUs. Where you can get the SDK in this link.
Fortunately, SDK provides a getting started called "Getting Started with MCUXpresso SDK CMSIS Packs".
At the same time, MCUXpresso Ecosystem offers config tools, where is an integrated suite of configuration tools, is designed to guide customers from first evaluation to production software development.
This link has many trainings that could help you to learn more about how use config tools, also in the same link you can see the file called MCUXpresso Config Tools User's Guide (IDE) that could be helpful.
BR
Habib.