You don’t say which model of Nexus switch you have (initially), but this is a common problem thanks to Cisco having little forethought with regard to storage space (among many other things).
One option is to use the Compact images rather than the “full” images. See below for details and explanation.
Early models of Cisco Nexus 3000, 3100, and 3500 Series switches with a model number that does not end in -XL have 1.4 to 1.6 gigabytes of storage space allocated to the bootflash. Over time, the file size of NX-OS software images has steadily increased to be over 1 gigabyte. As a result, it is difficult for Nexus 3000, 3100, and 3500 Series switches with a model number that does not end in -XL to simultaneously store more than one full NX-OS binary image at a time. Therefore, administrators cannot follow the standard NX-OS software upgrade procedure on Nexus 3000, 3100, and 3500 Series switches with a model number that does not end in -XL that is used for other Nexus platforms, such as Nexus 5000, 6000, 7000, and 9000 Series switches.
Starting with NX-OS software release 7.0(3)I3(1), the file size of NX-OS software images can be reduced through the NX-OS Compact Image procedure. This is a non-disruptive procedure that does not affect the switch's control plane or ability to forward data plane traffic.
This is an excerpt from https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus3000/sw/upgrade/7_x/b_Cisco_Nexus_3000_Series_NX_OS_Software_Upgrade_and_Downgrade_Release_7_x/b_Cisco_Nexus_3000_Series_NX_OS_Software_Upgrade_and_Downgrade_Release_7_x_newGuide_chapter_01.html#id_61530
You could possibly use the compact image as a temporary solution in order to get rid of the “full” image from the device to free up space so that you can replace it with the “full” image you actually want to run (use the compact image as a placeholder).