We study the transition between integrable and chaotic behaviour in dissipative open quantum systems, exemplified by a boundary driven quantum spin-chain. The repulsion between the complex eigenvalues of the corresponding Liouville operator in radial distance s is used as a universal measure. The corresponding level spacing distribution is well fitted by that of a static two-dimensional Coulomb gas with harmonic potential at inverse temperature β ∈ [0, 2]. Here, β = 0 yields the two-dimensional Poisson distribution, matching the integrable limit of the system, and β = 2 equals the distribution obtained from the complex Ginibre ensemble, describing the fully chaotic limit. Our findings generalise the results of Grobe, Haake and Sommers who derived a universal cubic level repulsion for small spacings s. We collect mathematical evidence for the universality of the full level spacing distribution in the fully chaotic limit at β = 2. It holds for all three Ginibre ensembles of random matrices with independent real, complex or quaternion matrix elements. arXiv:1910.03520v4 [cond-mat.stat-mech]