Nickel chelate resins recognize two exposed histidines for an appreciable retention of a protein and it is recommended in the majority of the cases. This resin works well with relatively easy to separate His-tagged proteins.
High Density Nickel provides a higher amount of available groups and usually allows for higher binding capacity. The resin is adequate to work in batch or column purifications (Low Flow).

REFERENCES

• Lechner, Horst et al. “Library of Norcoclaurine Synthases and Their Immobilization for Biocatalytic Transformations.” Biotechnology Journal 13.3 (2018): n. pag. Biotechnology Journal.
• Marsden, A. P. et al. Investigating the Effect of Chain Connectivity on the Folding of a Beta-Sheet Protein On and Off the Ribosome. Journal of Molecular Biology 430, 5207–5216 (2018).
• Sanchez-Rodriguez, Ana et al. “Recombinant Rabbit Beta Nerve Growth Factor Production and Its Biological Effects on Sperm and Ovulation in Rabbits.” PLoS ONE 14.7 (2019): n. pag. PLoS ONE.