Hi Ramil:
MK61 belongs to K70 series and NXP does not support it in SDK. Currently no plan to support it in SDK.
One solution is to use MQX 4.2. which has MFS driver that includes support to Nand Flash and DDR memories.
So we can create a new BSP for MK61 based on TWR-K70F120M, which has a MCU quite similar to K61,
you also can use bare metal project.
Regards
Daniel