Decomposition products of hexaurea-chromic-chloride-trihydrate
Using the article Klaus Warzecha linked to and some trial-and-error, a possible decomposition could look like this and is in accordance with the TG diagram in the question:


Decomposition of $\ce{3 H2O}$ and $\ce{2 CO(NH2)2}$:
$\ce{[Cr(CO(NH2)2)6]Cl3 $\cdot$ 3 H2O -&gt; [Cr(CO(NH2)2)4]Cl3 + 3 H2O \uparrow + 2 CO(NH2)2 \uparrow}$
Decomposition of $\ce{2 CO(NH2)2}$ and $\ce{2 HCl}$:
$\ce{[Cr(CO(NH2)2)4]Cl3 -&gt; CrH6C2N4ClO2 + 2 CO(NH2)2 \uparrow + 2 HCl \uparrow}$
Decomposition of $\ce{2 CO2}$, $\ce{N2}$, $\ce{3 H2}$ and $\ce{1/2 Cl2}$ and oxidation of $\ce{Cr}$ to form $\ce{CrN2}$:
$\ce{CrH6C2N4ClO2 -&gt; CrN2 + 2 CO2 \uparrow + N2 \uparrow + 3 H2 \uparrow + 1/2 Cl2 \uparrow}$


Given the temperature range and pressure (probably standard pressure), the formation of $\ce{CrO2}$ is unlikely.