Tighten up spacing between nodes
\tikz[start chain=bitcoin going below,
start chain=depositor going below,
start chain=tbtc going below,
- start chain=ethereum going below]{
+ start chain=ethereum going below,
+ node distance=2cm]{
\node [on chain=bitcoin] (bitcoin label) {\underline{Bitcoin}};
\node [on chain=depositor] (depositor label) [right=3cm of bitcoin label] {\evenunderline{Depositor}};
\node [on chain=tbtc] (tbtc label) [right=2cm of depositor label] {\underline{TBTC}};
