The ıquiver algebras were introduced recently by the authors to provide a Hall algebra realization of universal ıquantum groups, which is a generalization of Bridgeland's Hall algebra construction for (Drinfeld doubles of) quantum groups; here an ıquantum group and a corresponding Drinfeld-Jimbo quantum group form a quantum symmetric pair. In this paper, the Dynkin ıquiver algebras are shown to arise as new examples of singular Nakajima-Keller-Scherotzke categories. Then we provide a geometric construction of the universal ıquantum groups and their "dual canonical bases" with positivity, via the quantum Grothendieck rings of Nakajima-Keller-Scherotzke quiver varieties, generalizing Qin's geometric realization of quantum groups of type ADE.2010 Mathematics Subject Classification. Primary 17B37, 18E30. Key words and phrases. Hall algebras, ıquantum groups, quantum symmetric pairs, NKS categories and quiver varieties. MING LU AND WEIQIANG WANG 4.1. Strongly l-dominant pairs (v, w i ) 23 4.2. Strongly l-dominant pairs (v, w ij ) 26 4.3. Strongly l-dominant pairs (v, w ijk ) 30 5. Computation in quantum Grothendieck rings for ıquivers 32 5.1. A bilinear form 33 5.2. Computation for rank 2 ıquivers, I 35 5.3. Computation for rank 2 ıquivers, II 37 5.4. Computation for rank 2 ıquivers, III 39 6. Geometric realization of ıquantum groups 41 6.1. Quantum groups 42 6.2. Theorems of Hernandez-Leclerc and Qin 42 6.3. The ıquantum groups 44 6.4. Decomposition of R ı 45 6.5. Filtered algebra R ı 49 6.6. Generators for R ı 51 6.7. Realization of ıquantum groups 53 References 54