ECU and TCM do not show up on my scan tool?

What was the reason to replace both parts? Failure or? If they are not showing up, then it is likely that they need to be programmed to operate in your vehicle. They are not plug and play items unless they are brand new and never initialized, even bench testing them on typical equipment can make them into bricks unless you use the OE tool and web site to program them. The way it is supposed to work is that you test the vehicle, discover the ECM is bad. You buy a new ECM from the dealer and install it. That ECM talks to the original BCM and loads a configuration from it. Then you program in the keys. Or the BCM is bad, you replace it with a new one and initialization takes place from the original ECM. Replace both at the same time and now you need to use the Consault to program both. Then you can initialize the keys.
Looking at the part numbers the ECM should be either 23710CB820 without dynamic stability or 23710CC23C if it has stability control.
The BCM depends on the trim level and option package but the number you posted doesn't show on the attached list.

That would be the problem. The used parts need to be programmed first. Normally I do the ECM first then any other modules.

Because it is used you also don't really know if it works. However, we will assume it does. You need a scan tool or laptop that can use a J2534 device to program the modules, then you go to https://www.nissan-techinfo.com/J2534.aspx and verify that the software will work with your device. Then you pay them and install the software and use it to re-program the ECM. Then you use it to program the BCM. Once they are both finished, they should now show up in the system and let you program the keys back in.
If you have never done JBox programming there are a lot of videos about it on YouTube.
Like this one - https://www.youtube.com/watch?v=6s1hC1gqfl8
and this one - https://www.youtube.com/watch?v=l-Dvir4CEV4

Looks like it needs the OEM reflash. At least that is what I would expect with any used ECU as they need to have the correct VIN and more to operate. The Part number is the same for a few different models, it is the software that gets installed that makes it work with your car.
That Autel should have came with a J2543 box. However, you still need the Nissan specific programming software. The Autel may allow you to use it but check the list at Nissan about the hardware needed as some makes are very specific about the tools used.

You're welcome. Hope it programs properly on the first try. I've had to fight with a few of them. Be sure to have a charger/power supply connected and the programming tools hardwired. You don't want signals to get corrupted.

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