The ONC program has been audited by core developers and will be audited by more third-party audit agents. The security & validity of the code is on a best-effort basis. No software is perfect, and there are inherent risks in trusting programs to manage assets.
The collateral backing the value of $CHAOS is a diversified reserve of stablecoins. The economic theory of the program operates on the assumption that its stablecoin reserves will hold their value, but stablecoins themselves contain inherent risk. Regulation and algorithmic errors can possibly affect their price. Holders of $CHAOS and $ORDER have diversified exposure to this risk, but that does not entirely eliminate it.
In general, $ORDER and $CHAOS are lower risks than a single stablecoin, due to their diversification.