According to Apple: https://support.apple.com/en-us/HT204360
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Using third-Party USB-C power adapters
Your MacBook will charge from USB-C power adapters not manufactured by Apple if they adhere to the USB Power Delivery specification.
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It doesn't appear Trent claims adherence to the "USB Power Delivery specification" ("PD") for the NT120R. That doesn't necessarily mean it can't charge a MacBook, but Apple probably won't claim that it should or could work unless Trent builds a USB-PD-spec-conforming battery/charger.
According to Anandtech: http://www.anandtech.com/show/9136/the-2015-macbook-review/6
"Apple’s included [MacBook] 29W charger can deliver 2A @ 14.5V for devices that comply with the USB power delivery specification, and 2.4A @ 5.2V for older USB battery charging devices (phones, tablets, etc)."
Trying to charge a MacBook with something (not USB-PD compliant) that only provides 5V (regardless of current?) may not work at all or work only slowly? Again, Apple only claims support for chargers that, "...adhere to the USB Power Delivery specification."