Yes.

The preferred way to use XSplit with Loola is via RTMP mode:

Select RTMP mode in Loola:

You should find your RTMP Key and Server URL:

In XSplit, set up new custom RTMP:

Set Encoder Parameters and your Loola RTMP Key + URL:

Set the x264/H.264 profile to "main" by entering "&ex:profile:main" in extra encoder parameters:

Also make sure to set keyframe every 2 seconds and Strict CBR mode.

See additional encoder parameters here:
​https://www.xsplit.com/blog/how-to-specify-extra-encoder-parameters

In order to work with Portrait resolutions, you will need to add those resolutions first in XSplit:

Next, select the newly added resolution: